null == "" is true?

[Salih Dincer]

On Tuesday, 12 July 2022 at 22:58:32 UTC, Steven Schveighoffer 
wrote:
> ```d
> string a = "abcabc";
> assert(a[0 .. 3] ==  a[3 .. $])
> assert(a[0 .. 3] !is a[3 .. $])
> ```
>
> The point is, `==` compares *value*, `is` always compares 
> *identity*.

Consider null type array which is a related topic but it cannot 
get a null element!  The first is ok, but the second is legal. So 
no effect, is it normal?

```d
auto p = [ null, null ];//*
   assert(
     is(typeof(null)[] :
        typeof(p)
     )
   ); /* and it has two(2) elements */

   p ~= null;             // okay
   assert(p.length == 3); // true

   p ~= [];               // legal (no error)
   assert(p.length != 4); // what! (no effect)

   assert(p[0] == []);    // true
   assert([] == null);    // right on

   import std.stdio;
   typeid(p).write(": ", p.length);
   writeln("->", []); // typeof(null)[]: 3->[]
```

SDB at 79